How to get Non-linear state space equations of a model (including blocks of vehicle dynamics toolbox)?

I want to get the non-linear state space equations of wheel block, taking the input as brake pressure and output as longitudinal slip. I want to design Sliding mode control for longitudinal slip control, therefore I need the non-linear state space model.

I have used system identification toolbox but it is giving only 6-7% best fit data which is not useful for controller design.

Answer 1

[Khaled Aljanaideh]

Hi Kartikey,

There are currently no features in the system identification toolbox that generate a nonlinear state space model from input-output data. However, if you have a state space model of the system and you would like to estimate the values of some parameters of this model, then you can consider estimating a nonlinear greybox model, please see this documentation page:

https://www.mathworks.com/help/ident/ref/iddata.nlgreyest.html

There are several examples on how to estimate a nonlinear greybox model, please see this page

https://www.mathworks.com/help/ident/examples.html?category=nonlinear-grey-box-models&s_tid=CRUX_topnav